The present invention relates generally to logic circuits, and more specifically to a logic circuit whose configuration is selectable.
Logic circuits being configurable upon command are well known and exemplified by U.S. Pat. No. 4,233,524 to Burdick. Switchable devices in the transmission path between the input transistors and the output control the logical configuration. Another example of switchable logic is a time shared programmable logic array in U.S. Pat. No. 4,084,152 to Long et al. In this patent, the drains of the transistors of the OR matrix 20 are either permanently connected to ground, permanently unconnected, or connected by switch elements 40 or 42 such that the configuration of the OR matrix may be modified or used on a time shared basis. The Lang et al patent deals with single switches or transistors at each of the intersections to form the OR matrix and not complex logic gates including a plurality of complementary field effect transistors to form the logic gates.